Now that spring is almost here it may be told. Throughout the siege of a
winter that brought epic snowfall, the inland Northwest's vole population has
made idleness a family value. Like mammals of many kinds, voles would normally
time their breeding with the return of sunlight, but this year, beginning in the
dark days of January, evidence of animal passion has transformed the
neighborhood where I live and taken on the shape of a portent. Grass-lined
runways crisscross our footpath from the back door; burrows pock the
snow-flattened weeds, and owl pellets found beneath the big cottonwood are
studded with tiny mandibles. Skittering, gray-brown shapes distract me while I'm
shoveling the drive. Scavengers animate the compost heap.

Poor Fatso, the family cat, despairs of husbanding her once orderly game
ranch. The voles have outbred her blood lust, it seems, and their uneaten
corpses strew the decks and walkways. She used to consume all except the
stomachs of her prey. As their population swelled, she began to leave the
hindquarters, then all but the heads. Finally, as engorged as the
Trojan horse, Fatso watches fresh generations of voles gallop past like so many
buffalo. The squeals of rutting males must invade her dreams.

At least a dozen species of vole inhabit the Northwest, including rarities
like the needle-eating red tree vole, which spends its entire lifespan in the
branches of old-growth firs, and the feisty, swift-kicking water vole. But given
the dryness of the mountain valley I live in, the voles we're seeing are most
likely Microtus pennsylvanicus, a blunt-nosed, short-tailed, lemming-like
creature with tiny round ears. Most people know it as the field mouse, but with
its swift metabolism, Microtus is a wolf among pipsqueaks. In addition to
the fungi and tubers it eats, it relishes seventy species of grass seed,
especially cultivated varieties, and it loves to girdle fruit tree saplings with
its chisel-like teeth. The meadow vole can be destructive, though hawks, snakes,
and coyotes would be hard pressed without it. Anything that eats meat eats
voles.

Still, when you reckon all its qualities, the vole's breed lust stands out.

Meadow voles live one year at best—a few months on average—yet females can
reproduce from the age of three weeks. Both sexes attract each other with
scented oils they release by grooming. After they mate, gestation lasts
twenty-one days and produces up to a dozen young; a mother vole may easily raise
eight or ten litters if she's lucky, though one in captivity gave birth to
seventeen. Theoretically, a female meadow vole can leave a million descendants.

So it is that nature provides more than just predators for rodent control:
the crowded conditions of population peaks lead to stress, like what humans feel
at rush hour. If this winter's voles follow precedent, then famine, disease, and
even mental derangement will get them, eventually. Overpopulation also causes
intraspecies aggression and vast refugee migrations, but while it has been shown
that migrants enjoy the highest reproduction rates, these are the ones most
conspicuous to predators—who even the score. Sources tell me that vole
populations spike every few years and that these are followed by cycles of crash
and recovery.

It's good for people that we can predict this. Voles are curiosities to those
of us with town jobs, but the grain industry considers them a major pest. The
dusting of crops with hydrocarbons is easily mis-timed, and bait shyness often
renders "rodenticides" useless. Opposed though many of us are to
agricultural poisons, it's daunting to imagine the plight of farmers in
Scotland, who deal with a parallel threat in the mountain hare. This animal
alternates between scarcity and abundances so extreme they constitute
"plagues," but unlike the meadow vole, its growth spurts are
patternless. Peaks recorded during a forty-year span occurred in 1930, 1931,
1941, 1953, 1958, and 1971. Horrendous livestock die-offs and economic freefalls
followed each of these years.

As for the meadow vole, researchers know more about when to expect its
boom years than why they occur. They used to think that lemmings, hares,
and other creatures like the vole existed in a state of balance, their
supposedly even-keeled reproduction upset only because of human influence. This
would have accounted for undeniable fluctuations like the one I'm seeing, but
the theory was shelved when small mammals of the tundra, where few people live,
showed the same behavior as their kin to the south. For now, population
biologists find consensus on only a few points. First, while enemies cannot put
brakes on vole expansion, they can delay a post-crash recovery: one O. P.
Pearson found that predators devoured 88 percent of a low-cycle vole
"crop." Second, voles are like anyone else—they depend on their food
supply. If they overgraze an area they have to abandon it or starve. Finally,
it's agreed that these variables cause changes within the animals themselves.
Big, randy aggressors dominate, touching off orgiastic mating, mass dispersal,
and another predatory bacchanalia.

For Microtus and genus Homo alike, babies are us. Not that
recognition brings hope of change in human behavior, but Samuel Zeveloff, author
of Mammals of the Intermountain West, puts the writing on the wall where
it belongs: "Human populations exhibit some of the same dynamics at
increasing densities as do small mammals." The gene's quest for
immortality is the meal ticket of the unborn. And there seems to be no
circumstance too squalid to keep our progeny from coming. All this lends to the
drama taking place in my backyard, the sniffiness of a cautionary tale. But no
matter. The interest lies in its details.

Voles, voles, voles. If voices had odors, the squeak of this animal would
remind you of cheese. It is a sharp and pungent sound, as high-pitched to the
ear as the taste of salt on the tongue. Right now there's a magpie flaying a
vole on a stump beyond the kitchen window, tossing its live meal in the air and
catching it again in its bill. With binoculars I can see crows in the neighbor's
hay field doing the same. A black lab that lives around here is bouncing along
the front walk with a vole riding in her jaws. Yesterday, I lifted a drowned
vole from the birdbath.

Death has no investment in the dignity of creatures. A vole may be impaled in
the talons of a prairie falcon, or a languid tabby cat may harry it a while,
leaving its victim grizzly and spazzing in a flowerbed. I scrape their remains
from the tire treads of my car with a stick. They get caught in the flooding
creek and snag with other flotsam in shoreline thickets. Shrikes hang their
carcasses on fence barbs.

Perhaps these cruelties explain the poignancy of voles in fables and
folklore. The field mouse of Aesop's story receives a rare kindness when, having
once pulled a thorn from a lion's paw, it is saved from drowning by the king of
beasts. Mice in the Brothers Grimm are betrayed by other animals ("The Cat
and the Mouse in Partnership") or by fate itself ("The Mouse, the
Bird, and the Sausage"). When my son was small, he read a picture book
called Mousekin's Golden House, in which the main character flees from an
owl to the inside of a cozy jack -o'-lantern.

Such stories may allay human fears, but this year's vole outbreak puts
fatality in our faces. Both voles and people live within rumor's reach of
slaughter. We are bred for tooth and claw. Starvation and land mines take us.
Microbes gnaw at our vitals. In rich countries we fade in oncology wards or
stare past the eyes of our loved ones into the slow-moving fog of dementia. The
only relief, it seems, is in getting born among the scarce. How many of its own
kind, crumpled in death, does a whooping crane have to look at?

All this raises the stakes on our days. In meadow vole years, the average
American lives to the ripe age of 547, allowing plenty of time to study music
and cloud stacks, or the ankles of women in summer dresses. Perhaps our destiny
is linked with the vole's in a positive sense, too. I have seen a vole
expressing something like happiness. Today, in back of my house by the propane
tank, I watched this vole feeding on stalks of grass. It held the blades between
its forepaws, gnawing them through till they tumbled and let the seed heads come
within its reach. The animal was so delicate I could have blown it over with a
sneeze. When I placed a sunflower kernel nearby, it was undisturbed, but
snatching it up, it gave it a quick spin and hustled away with the cache. A vole
can eat endlessly and never gain on the future. Even so, as I watched the same
doomed creature a few minutes later, grooming itself in a glade of chickory,
blinking its dark eyes and basking for a spell, it seemed to enjoy a share of
warmth in the world.